Stabilized radio tracking system



3 Sheets-Sheet l H. HARRIS, JR

April 5, 1955 STABILIZED RADI TRACKING SYSTEM Original Filed Feb. 15

April 5, 1955 H. HARRIS, JR

STABILIZED RADIO TRACKING SYSTEM 3 Sheets-Sheet 2 Original Filed Feb.l5, 1943 April 5, 1955 H. HARRIS, JR

STABILIZED RADIO TRACKING SYSTEM 3 Sheets-Sheet 3 Original Filed Feb.l5, 1943 -lNvENToR 0 ?[erbert Harrf/s, J2.

ATTORNEY United States Patent O STABILIZED RADO TRACKING SYSTEIVIHerbert Harris, Jr., Cedarhurst, N. Y., assigner to The SperryCorporation, a corporation of Delaware Continuation of applicationSerial No. 476,099, February 15, i947. This application July 21, 1947,Serial No. 762,297

6 Claims. (CI. 343-14) This invention relates in general to stabilizedlire control systems and particularly to arrangements for stabilizingautomatic radio gun control systems for use on ships or aircraft.

This application is a continuation of my prior application Serial No.476,009,v tiled February 15, i943, for Stabilized Radio Gun ControlSystem, now abandoned.

Some prior systems for stabilizing radio sights and gun controls havemounted the stabilizing gyro on the scanner to stabilize the scanner.Such a system is described and claimed in U. S. Patent No. 2,660,793,dated September l, 1953, in the names of C. G. Holschuh et al. Otherelements in such systems were stabilized by servo devices for followingthe scanner. However, the scanner, of necessity, is usually mounted insome more or less vulnerable position on an aircraft or ship. For thisreason, it is sometimes desirable to have the stabilizing gyro aseparate unit from the scanner.

In Patent No. 2,414,1308 for Stabilized Gun Control and Tracking System,dated Ianuary 14, 1947, in the names of R. C. Knowles et al., agyro ismounted separately and is utilized to stabilize the scanner, computer,and other elements of the system. However, a target can only be trackedby moving the scanner in accordance with either radio signals orsignals' from a manual control. ln such cases it is necessary for thegyro to follow the movements of the scanner. Thus, two independentelements control the position of the scanner, namely, the trackingAcontrol and the stabilizing gyro.

ln the prior systems, data supplied to the computer was determinedthrough a chain of movements whereby either a radio or optical sight ismoved by a suitable radio or manual control and movements of the sightapplied torques tothe gyro, which, in turn, supplied data to thecomputer. In the present invention data is snpplied directly from thesight controls to the gyroand then to the computer, thereby securing aSmooth integrated control.

According to the present invention, the gyro is mourted separately fromthe scanner, and is used to stabilize the scanner, au optical' sight andother elements of' the lire control system including a computer. Eitherradio or manual controls are actuated to energize a torque motor forapplying torque tor the gyro thereby causing it to precess at a rateproportional to the rate of movement of the target'. The same mechanismsused for stabilizingV the various elements are also utilized for causingthe other mechanisms to follow the precession movements of the gyro. Itwill be apparent that this reduces to a minimum the mechanisms requiredfor stabilization and tracking.

Since the gyro is mountedV separately from the scanner, it is not aslikely to be damaged during operations against an enemy. Irl the scanneris damaged, it is: still possible to continue using the stabilized'vsystem with. an optical sight and a manual tracking control. Similarly,if the optical sight is damaged, a stabilized radio control system willbe available for continuing operations. It will appear from thetollowing'description that provision is made for an automatic trackingsystem actuated by a radio sight and a manual tracking system which maybe used with either a radio sight` or an. optical sight. The computer issupplied with accurate data whether radio or manual tracking controlsare used.

As will subsequently appear, the` gyro may either be mounted integrallywith the computer or separately therefrom.

2,705,792 Patelgted Apr. 5, 1955 One objectof the invention is to'provide a simplifiedv arrangement for stabilizingl a radio gun controlsystem.

Another object' of the invention is to provide a stabilized radio vguncontrol system in which the stabilizing gyro also controls theorientation adjustments of all of the elements of the system. l Y

A still further object'of the invention is to provide a radar system inwhich 'tracking controls are connected directly' to the gyr'o-fororienting the various elements of the system and supplying rate andorientation data to the computer.

Of course, it lwil'lbe understood that my system, or the maincomponents' thereof, has application in other fields and? for otherpurposes than the control of guns. Obviously, my device may be. used inany system in which it is desired tol orient or furnish a guide for anobject toward or with.` reference to what l broadly term a target, thatis, a second object or reference. In such systems, the radiant energytransmitted from such target to the guided object is used fordetermining the line of sight between the two objects. Such radiantenergy'may originate from a source on the target or be reflected by thetarget from. a source at the guided object or elsewhere.

Other objects and advantages of the invention will become apparent; fromthe following description taken in connection with the accompanyingdrawings wherein:

Fig. lV is a schematic block diagram showing a gun control systemembodying the invention.

Fig.. 2 is aY schematic block diagram similar to Fig. l but showing aimodified gun control system.

Fig. 3" is a schematic perspective view of a gyro elementdandv followerused in the systems shown in Figs. l an 2.

Fig. 4= isa schematic wiring diagram showing an arrangement forcontrolling the torque: motors, and

Fig. 5 is a schematic perspective View of a manual eontrci devicesuitablev for use in the systems shown in Figs. l and 2.

Referring rst to' Fig'. 1^, a. complete lire control system is shownlfor either elevation' or azimuth controlling devices. SincetheControls:` for elevation and azimuth are identical,v it; is believedthat ay description of one will suhce `for both` and' will avoid.unnecessary complexities in the drawings as well-as the description.

The system shown inrFig'. 1v includes a radio sighting stationunit-designated generally at l and an optical sighting station unitdesignated generally at 2, which are selectively connected `tol a gyrocomputing unit designated generally at 3.

In the radio sighting station, a scanner 5 is provided for projecting'radiant` energy toward the target 6 and receiving. reections therefrom.TheV scanner 5 includes a directional antenna 7 that is mounted formovement about mutually perpendicular-,axes hereinafter called the nodtyand` spin aires; The antenna 7 may be continuously rotated or spun at aconstant speed about the spin axis. and oscillated at a somewhat slowerspeed about the nod axis.

When bothispinning and nodding movements are applied to the antenna, thedirectional beam radiated will describe a spiral pattern. If the noddingmotion is stopped and the axis of the reflector of the antenna 7 fixedin a' position offset with: respect to the spin axis, continuation ofthe spinning. will describe a conical patt tern with the directionalbeam.

The scanner 5 is also mounted for movements in azimuth about a verticalaxis and for movements in elevation about a horizontal axis. Only theazimuth movement is shown in the drawing whereby the scanner isrotatable about aivertical axis as by means of a shaft 8. A similarhorizontal shaft would serve to rotate the scanner in elevation.

The radio sighting' station also includes a transmitter 11 that may beof any suitable design for supplying radio freqeucy energy to theantenna 7. This transmitter may generate relatively' high frequencyradioV energy modulated by short pulses. For convenience" in thedrawings, the` transmitter 11 is shown mounted integrally with thescanner. However, it may be placed at any convenient position and' the'radio energy supplied by means of suitable wave guides and couplings tothe antenna 7.

A receiver 12 for detecting energy reflected from the target 6 to theantenna 7 is also shown as mounted integrally with the scanner. However,this is again a matter of convenience and may be varied in accordancewith the circumstances of specific installations. The receiver 12 is sodesigned that the reception of energy reflected from a target produces asignal corresponding Y to the orientation of the target with respect tothe spin axis of the scanner. This signal as will hereinafter appear-issupplied through a suitable smoothing ampli tier 13 to circuits forautomatically aiming guns or to indicating instruments which will showthe orientation of the target with respect to the guns. In the lattercase a manual control may be used to position the guns.

' The gyro and computer unit 3 includes a computer 15 which is of anysuitable design capable of utilizing present target position andtargetrate data for deriving aiming angles to direct guns toward thefuture position of the target and also to compensate for ballisticcorrections necessary to accurately position the guns. There are severaltypes of computers for solving the problem of directing guns toward thefuture position of a target. Some of these computers use accuratepredictions and some approximate predictions of the future position. Oneparticular computer suitable for use in the present system is shown inthe copending application Serial No. 492,408 for Inter-Aircraft GunSight and Computer, filed September 17, 1941, in the names of C. G..Holschuh et al., now abandoned.

In the system shown in Fig. 1, a gyro designated generally at 16 ismounted integrally with the computer. The gyro 16 is ofconventionaldesign and includes a gyro element 17 that is supported in ahousing o r base comprising follow-up member 18. Gyro element 17 is'free to move relative to the housing 18, relative movements about avertical gyro axis being detected by a suitable pick-Dif 19. Thepick-off 19 may be connected through an amplifier 21 to a follow-upservomotor 22 for moving the follow-up member. 18 in accordance withrelative movements of the element 17 about the aforementioned verticalaxis.

Only one pick-off for detecting movements about a vertical gyro axis isshown in Fig. l. However, a pick-off would also be arranged to detectrelative movements between the gyro element 17 and the housing 18 of thegyro about a horizontal gyro axis, that is, relative elevationmovements. of the gyro element 17.

A torque motor 23 is mounted on the housing to apply torque to one axisof the gyro element thus causing the gyro to precess about aperpendicular axis. The azimuth torque motor 23, shown in the drawing,applies torque about a horizontal axis thus causing the gyro to precessabout avertical axis.. This results in relative movement between theelement and the housing which is detected by the pick-off 19. Anelevation torque motor, not shown in Fig. 1, is also mounted on the gyrohousing and arranged to apply torque to the gyro element about avertical axis thusI vcausing precession of the element about ahorizontal axis. v

The details of'the gyro 16 may be seen more clearly in Fig. 3. The gyrorotor element 17 is mounted in a bearing frame 25 and is continuouslyrotated in the frame 25 about an axis A-A by suitable means not shown inthe drawings. As will subsequently appear, the spin axis A-A of the gyrois maintained parallel to the line of sight. The frame 25 is pivotallymounted in a vfirst gimbal ring 26 by trunnions 27 and 28 for movementin azimuth about a vertical axis B--B. The first gimbal ring 26 ispivotally mounted in a housing or base comprising follow-up member 18 bytrunnions 29 and 31 for movements in elevation about a horizontal axisC-C, and housing 18 issupported on the trunnion Bland shaft 32 in afurther base -comprising bracket support 33 for movements in elevationabout the horizontal axis C-C. Bracket 33 together with the housing 18is movable about the axis B--B in accordance with azimuth movements of ashaft 34.

A second gimbal ring 35 is pivotally mounted by trunnions 36 and 37 inthe housing or follow-up 18 for movementV about the vertical axis B-B. Ashaft 39 coincident with the spin axis of the gyro projects from therotor 17 into a slot 41 in the second gimbal ring 35 whereby the gimbalring 35 is moved about the vertical axis B--B in accordance with azimuthmovements of the gyro element. Elevation movements of the gyro about theaxis C-C cause .relative movement between the rst gimbal ring 26 and thehousing 18.

The housing 18 carries the azimuth torque motor 23 having its rotorconnected to the trunnion 29 on which the iirst gimbal ring 26 issupported. Current in the windings of the torque motor 23 will cause therotor thereof to apply torque to the trunnion 29 and which in turnapplies torque to the gyro element 17 about horizontal axis C-C. Anapplication of torque about the axis C-C will cause the gyro to precessin one direction or another about the vertical axis B-B depending uponthe direction of the applied torque. It is a well-known characteristicthat the gyro precesses at. a rate proportional to the torque applied.Thus the gyro precesses in azimuth at a rate proportional to the torqueapplied by the motor 23. Since the torque-of the motor 23 depends on thecurrent in its windings, it may be said that the gyro will precess inazimuth'in accordance with the current flowing in the azimuth torquemotor 23.

A similar motor 44 is also carried by the housing .18 for applyingtorque through the trunnion 36. This torque is applied about thevertical axis B-B and therefore causes the gyro to precess about itshorizontal axis C-C. The torque applied by the elevation torque motor 44will cause the gyro to precess in elevation at a rate proportional tothe current in the windings -of motor 44.

The torque motors 23 and 44 are energized by azimuth torque motorampliiier 46 and elevation torque motor amplifier 47, respectively.These amplifiers control the current in the motors 23 and 44 in a mannerto be more fully hereinafter explained.

In order to detect relative movement of the gyro 17 and its associatedgimbal rings 26 and 35 relativeto the housing or follow-up 1,8, thehousing 18 carries a pair of pick-offs designated generally at 19 and 48for detecting azimuth and elevationcomponents of the said relativemovement. The pick-c1119 is the same pick-'off as that shown in Fig. 1for detecting relative movements of the gyro and the follow-up inazimuth. The pick-oit 48 is similar to the pick-off 19 but is arrangedto detect relative movements of the gyro vand the housing in elevation.

These pick-offs may be of any suitable type depending upon theparticular construction of the gyro and other design factors. One typethat has been found suitable is a magnetic pick-off known asan Etransformer. As may be seen in Fig. 3, the Etransformer consists of athree-legged or E-shaped core 51 that is mounted -on the housing 18 byan arm 52. The core 51 has windings not shown in the drawings on eachleg. The center leg winding is energized from a suitable source ofalternating current (not shown). yThe windings on the two outer legs arearranged in series opposition, these two windings being connected bymeans of conductors 53 and 54 to an azimuth follow-up amplifier 21.

- An armature 55 is carried by the second gimbal ring 35 in a manner soit is positioned across the threel legs of the core 51. When thearmature 55 is in a neutral position relative to the three legs of core51,Y equal voltages are induced in the windings on the two outer legs ofthe core. Since these windings are connected in series opposition, therewill be no output as long as the armature 55 remains in its neutralposition. How. ever, when the armature 55 moves to one side or the otherof its Yneutral position, the voltage induced in the coil toward whichthe armature moves is increased and the voltage induced in the othercoil is decreased. Hence,

the voltage output of the two windings is a reversible phase voltagedepending upon the direction of the relative displacement and is of amagnitude corresponding to the amount of the displacement. -v

This output voltage form the pick-off 19 actuates'the follow-up amplier21 in a manner to cause the followup servomotor 22 to move the housing18 so the core 51 will be returned to its neutral position relativetothe armature 55. It will be apparent that the Vpick-off together withthe follow-up amplifier and servomotor keep the housing 18 continuallyin the same relative position in azimuth to that occupied by the gyroelement'17.

Similarly, the pick-oit 48 having core 56 and armature 57 mounted on thehousing 18, and thexrst gimbal ring 26, respectively,'detects relativemovement o f the housing and gyro element 17 in elevation. vThe outputof the pick-or 48 actuates an elevation follow-up amplier 61 that causesa suitable servomotor 62 to position the housing 18 to continuallymaintain it in the same relative position in elevation to that occupiedby the gyro element 17.

As may be seen clearly in Fig. 3, the servomotor 22 drives pinion 64that meshes with a gear 63 on the shaft 34 to rotate the supportingbracket 33 together with the housing 1S in azimuth. The servomotor 62drives through a diierential 65 to rotate a gear 66 that is formedintegral with a bevel gear 67. The bevel gear 67 drives a bevel gear 68,which, in turn, drives through a shaft 69 and gears 71 to rotate shaft72 and bevel gear 73. The bevel gear 73 meshes with a large bevel gear74 to rotate shaft 75 that is connected to the housing 18 to positionthe housing 18 in elevation.

Since the shaft 69 and gear 68 are carried by the supporting structurefor the housing, rotation of the housing in azimuth would cause the gear68 to walk around the gear 67 thereby changing the elevation position ofthe gyro. In order to compensate for this erroneous movement inelevation, the gear 63, which moves in azimuth with the gyro housing, isconnected to a gear 77 forming a second input for the differential 65.It will be apparent that rotation of the gear 63 together with thehousing 18 in azimuth will cause the output of the differential torotate the gear 66 the same amount whereby the gear 68 will bestationary relative to the gear 67.

Shaft 79 on the follow-up motor 22 is continuously positioned in azimuthin accordance with the position ot' the gyro housing. Since the spinaxis A-A of the gyro element is maintained parallel to the line of sightand the housing 18 follows movements of the ygyro, the azimuthservomotor 22 together with its shaft 79, will be continuouslypositioned in accordance with the azimuth position of the line of sight.Hence, shaft 79 may be mechanically connected to the computer 1S todrive the present azimuth position of the line of sight into thecomputer as clearly shown in Fig. l.

Similarly, the elevation servomotor 62 (Fig. 3) which is not shown inFig. 1, will drive its shaft 31 in accordance with the present elevationposition of the line of sight. This shaft may also be mechanicallyconnected to the computer 15 to drive the present elevation positiondata into the computer.

The azimuth follow-up motor 22 also drives through bevel gears 83 and 84to position the rotor of a position transmitter 35 in accordance withthe present azimuth position of the line of sight, The' positiontransmitter 35 may be of any suitable self-synchronous type such as aselsynj Autosyn, or Telegon and is energized from a suitablel source 86of alternating current. Since the rotor of the transmitter 3S ispositioned in accordance with the present azimuth position of the lineof sight, the output of the transmitter 85 will represent the presentazimuth position of the line of sight and may bev supplied by means of acable 87 to a pair of switches 88 and 89 for connecting this output toposition the radio sight and the optical sight. As will become apparentfrom the following description, either one or both of these sights maybe` connected to the transmitter SS.

When the switch 88 is closed, theA output of position transmitter 8Swill be supplied by a conductor 91 to a signal generator 92, the rotorof which is continuously positioned in accordance with the azimuthposition of the scanner S by means of bevel gears 93 which connect shaft94 of the rotor to the shaft 8 of the scanner. If the rotor of thesignal generator 92 is not in synchronous position relative tothe rotorof position transmitter 85, it will preduce` a signal. inV conductor 95to actuatey an amplifier 96 which operates a suitable servomotor 97 todrive the shaft 8 in a direction to position the axis of the scanner Sin parallel relationship with the azimuth position of the axis A-A ofthe gyro element 17. In this manner the axis of the scanner 5 iscontinuously maintained paralleli to the axis of the gyro element 17 andhence is stabilized in space.

lf the craft carrying this system changes its attitude, thev gyrohousingwill be moved relative to the gyro element since the housing will movewith the craft and the elemnt will remain stationary in space. Thescanner will also tend to move with the craft and the gyro housing.However, the relative rnovement'be'tween the gyro element 17 and thehousing 18 will he detected by the pick-off 19 which will act throughfollow-up servo 22 to reposition the housing 1S in accordance with theposition of the gyro. Movement of the housing 18 will move positiontransmitter S5 which will, in turn, act through signal generator 92 andservornotor 97 to reposition the scanner S so its axis will correspondwith the axis of the gyro element.

In a similar manner, when the switch 89 is closed, the output ofposition transmitter 85 will be connected through a conductor 99 to asignal generator 161, the rotor of which is continuously positioned inaccordance with the azimuth position of an optical sighting instrument1%2. rhe optical sighting instrument 1112 carries a telescope 103 thatis adapted to sight the same target 6 as is sighted by the radio sightand is positioned in azimuth by a shaft 1nd that is connected throughbevel gears 165 to shaft 166 on the rotor of the signal generator 101.

Generator 101 produces a signal that actuates an amplilier 197 tocontrol a suitable servomotor 108 which adjusts the azimuth position ofthe optical sighting instrument 102 to agree with the position of thegyro. rl`hus, the optical sighting instrument 192 will be stabilized inazimuth by the gyro and the line of sight of the telescope 163 willremain substantially parallel to the spin axis A-A of the gyro.

The elevation follow-up motor 62 (Fig. 3) drives through suitable bevelgears @2 to control the rotor of an elevation position transmitter 90,the stator of which is also connected to the source 86. This elevationposition transmitter controls the elevation position of the radio andoptical sight in the same manner as the transmitter S5 controls theirazimuth position. Signal generators, amplifiers and servomotors areprovided for the elevation controls and are connected in the same manetas the equipment for the azimuth controls.

The system shown in Fig. l may be used optionally with either automaticor manual tracking. A double throw, double pole switch 111 has itsswitch arms 112 and 113 connected to the smoothing amplii'ier 13 and atorque motor amplifier 46, respectively. When the switch 111 is in itsupper position A, the system is arranged for automatic tracking. Theoutput for the smoothing amplifer is then connected through switch arms112 and 113 to the torque motor amplifier 46 which, as previouslydescribed, controls a torque motor 23 to apply torque to the horizontalaxis C-C of the gyro.

in automatic tracking the antenna 7' is arranged for conical scanning aspreviously described. The output of the receiver 12 and smoothingampiilier 13 is proportional to the displacement of the target 6 fromthe line of sight, that is, the displacement from the spin axis of thescanner 5. rlhis output actuatcs torque motor amplier 46 to control thetorque motor 2.1 in a manner such that it will apply a torque to thegyro proportional to the azimuth component of the displacement of thetarget 6 from the spin axis of the scanner.

As is described in the above-mentioned Patent No. 2,414,108, suitablephase sensitive amplifiers reference voltages are used to ootain theelevation and azimuth components of the displacement of the target 6from the line of sight or spin axis the scanner.

When the line of sight is displaced from the target, torque motoramplifier 5.6 will torque motor 23 to apply a torque about the horizontl axis C of the gyro proportional to the azimuth component of thedisplacement of the target 6 from the line of sight or spin axis of thescanner. This torque will cause the gyro element 17 to process at a rateproportional to the torque applied. lf the target 6 is moving relativeto the line of sight, the torque applied will be proportional to therate of movement oi the target, and hence the gyro element 17 willprocess at approximately the same rate as the target is roving.

Procession of the gyro element 17' results in relative movement betweenthe gyro element 1'? -d the housing or follow-up 18. lence, pick-olf 19win elect this relative movement and will actuate azimuth f W-upamplifier 2.1 which controls azimuth follow-up servomotor 22 to move thehousing 1S in accordance with the movements of the gyro element. Thefollow-up servo 22 will also adjust the rotor of position transe t .er25S in accordance with movements of the gyro, and the voltage output ofposition transmitter 3S will thus act through signal generator 92,amplier 96, and servomotor 97 to position the spin axis of the scannerin yaccordance with the azimuth movements of the gyro.

From an examination of this circuit it may be seen that the spin anis orline of sight of the scanner 5 will follow movements of the target 6,and hence, automatically track the target. Similarly, movements of theposition transmitter 85 in accordance with movements of the target 6,will be applied through signal generator 101, amplifier 107, andservomotor 108 to adjust the position of the optical sight 102 tomaintain the line of sight of telescope 103 on the target.

' It is optional to have the telescope 103 as well as the scanner followthe target by opening or closing the Switch S9.

The output of torque motor amplifier 46 and its connections to thewindings of the azimuth torque motor 23 is shown in detail in Fig. 4. Asmay be seen, the output stage of the amplifier 46 consists of a pair ofelectronic tubes 111 and 112. When no signal is applied to grids 114gand 114, equal currents flow in the plate circuits of the two tubes,including windings 115 and 116 of the torque motor 23.y Since thesewindings are oppositely connected, no torque will be applied by themotor. Since the currents in the plate circuits of the tubes are equal,equal voltages will be developed across resistors 117 and 118 in thecircuits of cathodes 119 and 121 of the tubes 111 and 112, respectively.For these reasons, the voltage across output conductors 122 and 123connected to the cathodes 119 and 121 will be zero.

When a signal is applied to the torque motor amplifier 46, the voltageapplied to one of the grids will be made less negative and that appliedto the other grid will be made more negative. Assuming the voltage onthe grid 114:1 is made less negative, the current in the plate circuitof tube 111, including winding 115, will increase and the current in theplate circuit of tube 112, including winding 116, decreases. The torqueapplied by the motor 23 will be proportional to the difference betweenthe currents in the two windings. Similarly, the voltage betweenconductors 122and 123 will be equal to the difference between thevoltage drops across resistors 117 and 118. This difference is alsoproportional to the difference in the currents in the plate circuits ofthe two tubes, so the voltage across the two resistors, as taken off byleads 122 and 123, is proportional to the torque applied by the motor23.

Since the applied torque is proportional to the precession rate of thegyro and the gyro precesses at the same rate as the target 6 is moving,the voltage across leads 122 and 123 is proportional to the rate ofmovement of the target. This voltage is utilized to actuate a rate dataamplifier 131 (Fig. 1) which controls a rate data servomotor 132 that'isarranged to drive a shaft 133 in accordance with the rate of movement ofthe target 6.

The shaft 133 is connected through suitable bevel gears 134 to rotate ashaft 135 that drives the rate data into the computer 15. The shaft 133also drives a position transmitter' 136 which may be a potentiometerthat is energized from a suitable voltage source 137. As the shaft 133rotates to drive rate data in to the computer, the voltage output of thetransmitter 136 will be varied accordingly. This voltage output issupplied to the rate data amplifier 131 and compared therein to the ratevoltage from the torque motor amplifier 46.

The rate data amplifier 131 causes the rate data servo 132 to rotate theshaft 134 until the voltage from the Vtransmitter 136 is equal to thevoltage from the torque motor amplifier 46. When these voltages areequal, the shaft134 will have rotated an amount equal to the targetrate. It will be apparent that the shafts 133 and 135 will becontinuously positioned in accordance with the rate of the target and,therefore, rate data will be continuously supplied to the computer.

When the switch 111 is positioned as shown in the drawing for automatictracking, the output of the radio smoothing amplifier 13 may beoptionally connected to a radio indicator 141 by means of a switch 142.This indicator may be a cathode ray tube having its deecting platesconnected to the amplifier 13 in a manner to show the displacement ofthe scanners spin axis from the target. Thus, when the switch 14-2 isclosed, the indicator 141 Vwill provide the operator with a visualindication of the position of the line of sight (spin axis) of thescanner 5 relative to the target 6.

When it is desired to manually track the target 6, the

switch 111 is moved to its lower position M whereby the indicator' 141is connected by switch arm Y112 to thesmoothing amplifier 13 to give anindication of the position of the target 6 relative to the line of sightof the scanner 5. The torque motor amplifier 46 is connected throughswitch arm 113 to manual control 143 vthat may be of any suitable typesuch as that shown in Fig. 5.

The manual control shown in Fig. 5 includes handles or grips 151arranged in handle-bar fashion and adapted to be rotated about ahorizontal axis D-D of connecting shaft 152 in accordance with elevationmovements desired and about a vertical axis E-E in accordancel withazimuth movements desired. i

Movements of the grips 151 about the horizontal axisV DD cause the shaft152 to rotate a pinion 153 thatL engages a cylindrical rack 154. Therack 154 is connected by means of shaft 155 to another cylindrical rack156 which meshes with a pinion 157 to rotate a slide arm 158 of apotentiometer 159 in accordance with movements of the grips 151. Thepotentiometer 159 is connected across a suitable source of current 161and output con-A ductors 162 and 163 are connected to the mid-point ofthe potentiometer andthe slide arm 158, respectively. It will beapparent that the voltage across conductors 162 and 163 will be of asense corresponding to the direc-` tion of the movement of the grips 151and a magnitude proportional to the displacement of the grips 151 fromtheir neutral position. y v

Movements of the grips about the vertical axis .E--E cause rotation of abevel gear 165 which meshes with another bevel gear 166 to rotate slidearm 167 of a i potentiometer 168 in accordance with the movements of thegrips. Potentiometer 168 is connected across a suitable source ofcurrent 169, and output leads 171 and 172 are connected between themid-point of potentiometer 168 and the slide arm 167, respectively.Thus, movements of the grips 151 in azimuth will produce a voltageacross leads 171 and 172 corresponding in sense to the direction, and inmagnitude to the movement of the grips 151 from their neutral azimuthposition.

The outputs of potentiometers 159-and 16S are connected to the elevationtorque motor amplifier 47 and the azimuth torque motor amplifier 46,respectively. The manual control shown in Fig. 5 forms a convenientarrangement for manually applying torques to the gyro to cause it toprecess in azimuth and elevation to Yfollow a target Assuming the radiosightis being used, the operator will adjust grips 151 to position thespin axis or line of sight of the scanner until it is on the target 6 asshown by the indicator 141. Fig, l shows only the connectiony from themanual control 143 to the azimuth torque motor 46, the output whichcorresponds to the connections from potentiometer 168 to azimuth torquemotor v46. This connection is designated schematically as conductor 181,which is connected to switch arm 113 when the switch 111 is in its loweror manual position. As has been previously stated, similar equipmentwould be provided for the elevation control to apply signals from thepotentiometer 159 to the elevation torque motor amplifier 47 and causeprecession of the gyro in elevation by application of torque throughtorque motor 44 The manual tracking control may be used with either theradio or optical sights. When the optical sight is used, the operatorobserves the target through telescope 103 and moves grips 151 to precessthe gyro in accordance with movements of the target. As has beenpreviously explained, procession of the gyro will cause movements of theoptical sight in accordance with movements of the gyro.

Rate data is supplied tothe computer in an identical manner whethermaunal or automatic tracking is used. Formanual tracking a voltage fromtorque motor amplifier 46 will be supplied to rate data amplifier 131 inthe same manner as that previously described in connection withautomatic tracking. This data is 'identical in both cases because boththe manual and automatic tracking controls act to energize torque motor23 in a manner to apply torque to the gyro. Since the gyro processes ata rate proportional to the toque applied, it is immaterial insofar asthe computer is concerned whether the rate data is first controlledmanually or automatically.

During either manualV or automatic tracking either or both of the sightsmay be stabilized by the gyro and gAV eitlfler orv both of the sightsmaybe. arranged to follow movemments of the gyro'inaccordance withmovements thus preventing false rates due to Achanges in the atti-V tudeof the craft from being supplied tothe computer. Without thestabilization of the rates, the false rates introducedA into thecomputer would cause false predictions, thereby greatly reducingl theaccuracy of the system. Since these rates are determinedV by theprecession rates of the gyro, they are independent of movements ofthecraft and depend solely uopn movements effected to maintain the axis ofthe gyro element parallel to the line of sight. In this manner only trueor stabilizedrates are introduced for prediction computation in thecomputer.

Summarizing the operation of the system shown in Fig. l, the operatorfirst positions the switch 1,11 in the manual position M and useseitherthe radio sight o r the optical sight to pick out a desired target, Oncethe target isselected, the operator adjusts grips 151 to the manual`control to bring the line of sight onto they target. At this time, theswitch 111V mayl b e moved to its` automatic position A whereby theoutput ofA the radio smoothing amplier 13 will continually maintain theline of sight of the scanner ou the target. 1f either of the sights. isdisabled duringv operation, the other sight'may beV used` to continueoperation of the guns. Both sights arel available for use withA acompletely stabilized system and identical informationl is supplied tothe compuator 15.

On the basis of the present orientation position data and the rate datasupplied to the computer 15, the future position of the target ispredicted and gun aiming angles determined for directing the guns towardthe future position. These gun aiming angles may be transmitted to theguns in any suitable manner, as for example, by position transmitter185. Since all of the elements of the system are positioned inaccordance with the spin axis of the gyro, all of the elements will bestabilizedin space. Also, all of the elements will be continuously positioned in accordance with the line of sight the spin axis of the gyrois continuously maintained parallel to the line of sight.

The system shown in Fig. 2 is similar to that shown in Fig. l except thegyro unit is separated from the computer and the optical sightingstation is mechanically connected to the computer. The radio sightingstation 1 is identical to that previously described in connection withFig. l. The elements of the radio sighting station have been designatedby the same reference numerals, and it is believed that furtherdescription thereof is unnecessary. Similarly, a switch corresponding tothe switch 111 is arranged to connect the smoothing amplifier 13 to thetorque motor amplifier 46 or to the indicator 141 depending upon whetherthe switch arms 112 and 113 are in their upper automatic position A orlower manual position M. When in the lower position, the torque motoramplilier 46 is connected by switch arm 113 to the manual control 143that may be similar to the manual control previously described inconnection with Fig. 5.

The gyro unit is the same as that shown in Fig. 3 and includes the gyrorotor element 17 with its associated gimbal rings, housing 18 andpick-oli 19 for detecting relative azimuth movements between elements 17and housing 18. The pick-off 19 actuates the amplifier 21, causing thefollow-up servomotor 22 to adjust the position of the gyro housing orfollow-up 18 to correspond with the position of the gyro element. Thetorque motor amplier 46 is adapted to control the torque motor 23 toapply torque to the horizontal axis of the gyro to cause the gyroelement 17 to precess in azimuth at a rate proportional to the torqueapplied.

The follow-up servomotor 22 also adjusts the rotor of the positiontransmitter 85 in accordance with the azimuth position of the gyrohousing or follow-up member 18. The position transmitter is connected tothe signal generator 92 to continuously maintain the spin axis or lineof sight of the scanner parallel to the spin axis of the gyro 17.

instead of mechanically supplying the present azimuth positionof' thegyro housing to the computer as was done by shaft 79 in the previouslydescribed System, orientation data. is now eiectrically4 supplied to thecomputer. The output of position transmitter 85 is conneet-ed to asignal generator 191, the rotor of which is positioned in accordancewith shaft 19.2l thatA is adapted to drive present azimuth position datainto the cornputer 15 in a manner similar to that in which the same datawas supplied by the shaft 79. The rotor of the signal generator isconnected to the shaft 1312y by suitable bevel gears 193 and 194. Theoutput of the signal generator actuates an orientation amplifier whichcauses an orientation servomotor 196 to position the shaft 192 in.accordance with the azimuth position of the gyro. When the gyro changesits azimuth position, the change in the output' of position transmitter85 will act through signal generator 191 and. orientation amplifier 195to reposition the shaft 192 and also the rotor or", the signal generator191 in accordance with the change in azimuth position. ln this manner,the present azimuth position of the gyro is continuously driven into thecomputer by Shaft 192.

An optical sight 197, corresponding to the sight 102 in the previoussystem is mechanically positioned in accordance with the position-of thegyro by suitable gearing including a. bevel gear 1918 that meshes withthe gear 193` on the shaft 192'. Rotation ofthe shaft 192 drivesthrough` gears 193 and 198 to rotate shaft 2,61, gears202, shaft 203,gears 204', and shaft 205 to positiony the sight in accordance with the;position of the shaft 192. This maintains the linel of sight oftelescope 207 parallel to the spin axis ofthe gyro element.

Stabilized data corresponding to the rate-of. movement of the target issupplied to the computer 15 in the manner as this data was supplied inthe previously described system. A voltage from the torque motoramplifier 46 actuates the rate data amplifier 131 to control rate dataservo 132 which drives shaft 135 through suitable gears 134 to adjustshaft 135 in accordance with the rate of movement of the target.

Stabilization of this modified system is effected in substantially thesame manner as the system shown in Fig. l. The radio sight follows thegyro and is thereby stabilized. Electrical connections are substitutedfor mechanical connections to drive present orientation data into thecomputer. Since this orientation data is determined by the gyro element17, the data is stabilized in Space. The optical sight, being positionedin accordance with the orientation data supplied to the computer, istherefore also stabilized.

Computer 15 utilizes the stabilized orientation data and the rate datato predict a future position of the target and determine gun aimingangles for directing guns toward said future position. These gun aimingangles are transmitted to the guns by the position transmitter 135.

During automatic tracking operations, use of the indicator 141 isoptional, it being controlled by a switch 142 in the manner described inconnection with the system shown in Fig. 1. Either manual or automatictracking control may be used depending upon the position of switch 111.When manually tracking the target, the operator may observe the positionof the line of sight ot' the scanner 5 relative to the target by meansof the indicator 141 or he may observe the target through the telescope207. In either case a manual control 11i-3 is operated to cause the gyroto precess at a rate corresponding to the rate of movement of thetarget.

In both of the Systems described, changes in attitude of the craft areimmediately compensated by the action of the gyro which stabilizes thegyro housing, the sighting instruments, and the computer. Assuming the'target is not moving in space relative to the line of sight, the gyroelement 17 will remain stationary and changes Iin attitude of the craftwill be compensated by maintaining all of the elements of the system inpositions corresponding to the position or' the gyro element. When thetarget is moving, stabilized rate data is supplied to the computer.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A stabilized directive radio system comprising a directive antenna,means for supporting said antenna for freedom about at least one axis, agyroscope separated from said antenna and including a base and agimballed suspension thereon, means including a radio receiver coupledto said antenna for producing output signals varying according to thedirection of said antenna with respect to a target to be tracked, meanscoupled to said receiver and responsive to said output signals forapplying precessional torque to said gyroscope, means coupled to saidgyroscope suspension for providing a measure of the angular dispositionof the gyroscope spin axis with respect to said gyroscope base, andservo means responsive thereto for varying the position of said antennarelative to its base through an angle equal to the angle of displacementof said gyroscope with respect to said gyroscope base.

2. A stabilized directive radio system as defined in claim 1 and furthercomprising an optical sighting system including an optical sight, andservo means responsive to movement of said gyroscope for varying theposition of said optical sight through an angle equal to the angle ofdisplacement of said gyroscope with respect to said gyroscope base.

3. A stabilized directive radio system as defined in claim l and furthercomprising indicator means coupled to said receiver and responsive tosaid output signals for indicating the orientation of said antenna withrespect to said target, a manually operable device for applyingprecessional torque to said gyroscope, and switch means foralternatively connecting said radio receiver or said manually operabledevice to said torque applying means for tracking the target.

f4. A vstabilized directive radio system as defined in claim 3 andfurther comprising an optical sight and servo means responsive tomovement of said gyroscope for varying said optical sight through anangle equal to the angle of displacement of said gyroscope with respectto said gyroscope base. v

5. A stabilized radio tracking system comprising an orientable antenna,radio means coupled to said antenna for producing Voutput signalsvariable according to the direction of said antenna with respect to atarget tov be tracked, a gyroscope separate from said antenna comprisinga follow-up member and a gimballed suspension thereon supporting therotor element of said gyroscope, means coupled to said radio means forapplying precessional torque to said gyroscope proportional to saidoutput signals whereby said gyroscope changes position relative to saidfollowup member, means including pick-oli means von said follow-upresponsive to movements of said gyroscope for moving said follow-upmember back to its original relative position with respect to the gimbalmeans of said gyroscope, and means responsive to movementof saidfollow-up member to orient said antenna towards said target. v

6. A stabilized radio tracking system as deiined in claim 5 and furtherincluding a computer mechanism for positioning guns, and meansresponsive to movement of said follow-up member for supplying targetorientationV data to said computer for control positioning of the guns.

References Cited in the le of this patent UNITED STATES PATENTS EvansJuly 13, 1948

